16 Nov
2010
16 Nov
'10
1:27 p.m.
On 16 November 2010 19:17, Edward Z. Yang
It seems to me that there is a possibility we could reify some information that is traditionally specified in the documentation: that is, what functions must be defined by a minimal instance, which could then give GHC enough information to give meaningful warnings if not all functions for a minimal instance are proviced.
One could use a compiler pragma the defines possible sets of minimal definitions, e.g. {-# MINIMAL_DEF Num ((+),(*),abs,signum,fromInteger,(-)), ((+),(*),abs,signum,fromInteger,negate) #-} one could even add logical notation, like: {-# MINIMAL_DEF Num ((+), (*), abs, signum, fromInteger, (-) || negate) #-}